Automatically update timestamp for BUILD_DATE

* Instead of manually updating the timestamp whenever we run gn2bp, this will always
update the timestamp everytime Cronet is compiled.

Bug: 332528730
Test: m cronet_aml_base_build_date
Change-Id: I6b91cd4cfab97044f18aa6837717c5b75cacd1fc

Author: Mohannad Farrag

Android.bp

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 //
-// This file is automatically generated by gen_android_bp. Do not edit.
+// This file is automatically generated by gn2bp/gen_android_bp. Do not edit.
 
 build = ["Android.extras.bp"]
 
@@ -5839,7 +5839,7 @@ cc_library_static {
 cc_genrule {
     name: "cronet_aml_base_build_date",
     cmd: "mkdir -p $(genDir)/base && $(location base/write_build_date_header.py) $(out) " +
-         "1712072430",
+         "`date +%s`",
     out: [
         "base/generated_build_date.h",
     ],
@@ -5855,7 +5855,7 @@ cc_genrule {
 cc_genrule {
     name: "cronet_aml_base_build_date__testing",
     cmd: "mkdir -p $(genDir)/base && $(location base/write_build_date_header.py) $(out) " +
-         "1712072430",
+         "`date +%s`",
     host_supported: true,
     out: [
         "base/generated_build_date.h",

android/tools/gn2bp/Android.bp.swp

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 //
-// This file is automatically generated by gen_android_bp. Do not edit.
+// This file is automatically generated by gn2bp/gen_android_bp. Do not edit.
 
 build = ["Android.extras.bp"]
 
@@ -5839,7 +5839,7 @@ cc_library_static {
 cc_genrule {
     name: "cronet_aml_base_build_date",
     cmd: "mkdir -p $(genDir)/base && $(location base/write_build_date_header.py) $(out) " +
-         "1705445157",
+         "`date +%s`",
     out: [
         "base/generated_build_date.h",
     ],
@@ -5855,7 +5855,7 @@ cc_genrule {
 cc_genrule {
     name: "cronet_aml_base_build_date__testing",
     cmd: "mkdir -p $(genDir)/base && $(location base/write_build_date_header.py) $(out) " +
-         "1705445157",
+         "`date +%s`",
     host_supported: true,
     out: [
         "base/generated_build_date.h",

android/tools/gn2bp/gen_android_bp

@@ -1163,6 +1163,7 @@ class BaseActionSanitizer():
 class WriteBuildDateHeaderSanitizer(BaseActionSanitizer):
   def _sanitize_args(self):
     self._set_arg_at(0, '$(out)')
+    self._set_arg_at(1, '`date +%s`')
     super()._sanitize_args()
 
 class WriteBuildFlagHeaderSanitizer(BaseActionSanitizer):